This paper deals with the evaluation of the interaction between a safety barrier and a variable message sign (VMS) that is placed very close to the carriageways in order to reduce the length of the arm above the carriageways. The two issues addressed are the structural response of the VMS, in order to ensure that the structure will not fail under the impact of a heavy goods vehicle (HGV), and the effects of the secondary impact that occurs when the barrier or the vehicle hits the VMS structure. These issues have been analysed both in terms of overall performance of the barrier and of the resulting effects on the HGV itself. As a result, the minimum distance between the front of the barrier and the VMS support structure that will enable to have a performance fully compatible with the requirements of EN1317-2:2010 has been defined for a specific barrier/VMS system.